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That's all we know. X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001 autolearn=_AUTOLEARN X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: ysato@users.sourceforge.jp, qemu-devel@nongnu.org, Ahmed Karaman , aleksandar.qemu.devel@gmail.com, stefanha@redhat.com, rth@twiddle.net Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Richard Henderson writes: > On 5/19/20 9:21 AM, Ahmed Karaman wrote: >> The issue arose because the page crossings check in use_goto_tb() >> function is required only in the system mode. Checking it in both modes >> causes an unnecessary overhead in the user mode. > > It is not only required in system mode. > > You can see failures in user-mode if you modify executable pages, or chan= ge > their permissions with mmap. Such as if the guest program contains a > JIT. If we kept better track couldn't we just tb_flush() if a new +x region gets mmaped? I guess that would be sub-optimal compared to having a translation cache per mmap region. --=20 Alex Benn=C3=A9e